The enhanced virulence of very virulent infectious bursal disease virus is partly determined by its B-segment

There is a remarkable difference in virulence of infectious bursal disease virus (IBDV) strains ranging from sub-clinical infections for serotype 2 and cell culture adapted serotype 1 strains, to 100% mortality for very virulent serotype 1 strains in young SPF chickens. It is known that cell culture adaptation related attenuation is determined by distinct mutations in the hypervariable region of the VP2 outer capsid protein, encoded on the A-segment. Amino acid mutations in the hypervariable VP2 region however, offer no explanation for the difference in virulence of classical and very virulent serotype 1 strains. Here we show by in vitro and in vivo analysis of rescued segment reassorted IBDVs that virulence factors are not only located on the A-segment, but on the RNA Dependent RNA Polymerase (VP1) encoding B-segment as well. Insight into the virulence factors of very virulent IBDV will contribute to the improvement of live IBDV vaccines

Messenger RNA of Rauscher leukemia virus: identification and biological activity

Contains fulltext : mmubn000001_182671704.pdf (publisher's version ) (Open Access)Promotores : H. Bloemendal en H. Bloemers cum laudeX, 141 p

An Efficient Procedure for the Isolation of Polyribosomes from Tissue Culture

Contains fulltext : 142596.pdf (publisher's version ) (Open Access

Translation of oncogenic viral RNA and eukaryotic messenger RNA in the E. coli cell-free system

Contains fulltext : 142268.pdf (publisher's version ) (Open Access

Avian amyloidosis

Although amyloid deposits have been described for more than a century and a half, its proteinaceous and fibrillar nature was not revealed until after 1950. Biochemical characterization of amyloids has brought to light that several non-related proteins can re-organize into amyloid fibrils. In some domestic and caged wild birds, and especially waterfowl, amyloidosis is a well recognized pathological disorder and is an important cause of death in Anseriformes. Its regular occurrence in Galliformes has been recognized more recently, where amyloid deposits occur mainly in the joints in contrast to other species studied so far. Avian amyloidosis is systemic in nature, being classified by amino acid sequencing and, monoclonal and polyclonal antibodies as of the AA-type amyloid, also named reactive or secondary amyloid. The pathogenesis of both AA and other types of amyloidosis is a complex phenomenon that is not well understood. It has been shown that the occurrence of certain predisposing conditions and chronic infections, inflammations or tumours increase strongly the serum levels of the hepatic acute phase reactant serum amyloid A (SAA), the precursor protein of amyloid protein A (AA). Although an increased pool of precursor protein is necessary for amyloid to develop and while certain amino acid substitutions may favour amyloidogenicity giving rise to unstable intermediate protein conformations that easily re-organize into fibrils, the action of other factors which are discussed in this review, seems of vital importance at the initiation of fibrillogenesis. As the clinical symptoms of amyloidosis generally are non-specific, diagnosis requires histopathology following biopsy or necropsy. AA-amyloidosis is a fatal progressive disease in birds and other species. Currently no curative treatment is available, therefore special attention should be paid to prevention focusing on hygiene and avoidance of stress

Geen verband tussen TD en loopvermogen: onderzoekm locomotiestoornissen vleeskalkoenen

Orienterend onderzoek van PP, GD en ID naar de relatie tussen dunne mest en locomotiestoornissen bij kalkoenen. In dit artikel de resultaten van een onderzoek naar de relatie tussen tibiale dyschondroplasie (TD) en het loopvermogen van de diere

In vivo interactions between the proteins of infectious bursal disease virus: capsid protein VP3 interacts with the RNA dependent polymerase VP1

Little is known about the intermolecular interactions between the viral proteins of infectious bursal disease virus (IBDV). By using the yeast two-hybrid system, which allows the detection of protein-protein interactions in vivo, all possible interactions were tested by fusing the viral proteins to the LexA DNA-binding domain and the B42 transactivation domain. A heterologous interaction between VP1 and VP3, and homologous interactions of pVP2, VP3, VP5 and possibly VP1, were found by co-expression of the fusion proteins in Saccharomyces cerevisiae. The presence of the VP1-VP3 complex in IBDV-infected cells was confirmed by co-immunoprecipitation studies. Kinetic analyses showed that the complex of VP1 and VP3 is formed in the cytoplasm and eventually is released into the cell-culture medium, indicating that VP1-VP3 complexes are present in mature virions. In IBDV-infected cells, VP1 was present in two forms of 90 and 95 kDa. Whereas VP3 initially interacted with both the 90 and 95 kDa proteins, later it interacted exclusively with the 95 kDa protein both in infected cells and in the culture supernatant. These results suggest that the VP1-VP3 complex is involved in replication and packaging of the IBDV genome

Interactions in vivo between the proteins of infectious bursal disease virus: capsid protein VP3 interacts with the RNA-dependent polymerase, VP1

Little is known about the intermolecular interactions between the viral proteins of infectious bursal disease virus (IBDV). By using the yeast two-hybrid system, which allows the detection of protein-protein interactions in vivo, all possible interactions were tested by fusing the viral proteins to the LexA DNA-binding domain and the B42 transactivation domain. A heterologous interaction between VP1 and VP3, and homologous interactions of pVP2, VP3, VP5 and possibly VP1, were found by co-expression of the fusion proteins in Saccharomyces cerevisiae. The presence of the VP1-VP3 complex in IBDV-infected cells was confirmed by co-immunoprecipitation studies. Kinetic analyses showed that the complex of VP1 and VP3 is formed in the cytoplasm and eventually is released into the cell-culture medium, indicating that VP1-VP3 complexes are present in mature virions. In IBDV-infected cells, VP1 was present in two forms of 90 and 95 kDa. Whereas VP3 initially interacted with both the 90 and 95 kDa proteins, later it interacted exclusively with the 95 kDa protein both in infected cells and in the culture supernatant. These results suggest that the VP1-VP3 complex is involved in replication and packaging of the IBDV genome